The exercise industry has moved forward from using simple resistance techniques to create a resistive force to push against, to using heart rate monitors to determine actual physical exertion. Most recently, user power output on bicycles has gained acceptance as a more accurate determination of actual physical exertion. Power meters by several companies are available based on several approaches. Strain gauges that measure the forces applied to bicycle cranks attached to the pedals of a bicycle have been shown to be the most accurate, while strain gauges installed in the rear wheel hub measuring the forces applied to the wheel through the chain can also determine the power that a rider is exerting. Other techniques include measuring the chain vibration (although this has been shown to be less accurate).
Power measurement can significantly enhance ones ability to exercise in a controlled manner and can be used to determine direct physical improvements in both endurance and muscular power. When coupled with heart rate measurement, power and heart rate can be used to determine overall fitness improvements.
Unfortunately, the currently available power measurement techniques are only applicable to the traditional bicycle and have not been applied to the common exercise bicycle due to the significant cost of the power measuring devices which can exceed the cost of the exercise bike. CycleOp™ currently manufactures a commercially available exercise bike, commonly called a spin bike, although the cost of the bike is several thousand dollars due in large part to the power measurement device.
If a low cost technique could be found that provides repeatable power measurement, the significant advantages of current bicycle power measurement could be translated to exercise (spin) bikes in health clubs and private homes. This would allow more controlled exercise and would enable the user to determine actual improvements in fitness over time. Furthermore, current exercise bikes (spin bikes) are highly variable based on bike to bike comparisons, so that workouts are difficult to gauge from day to day. The implementation of a power meter would significantly improve the repeatability of the exercise experience on a day to day and even week to week basis.